Lifetime measurements in Xe120

Physical Review C, 2019

Lifetimes are measured for the low-lying states of 131 I and 132 Xe nuclei populated from the decay of radio-chemically separated Te fission fragments. The VENTURE array comprised of eight fast CeBr 3 detectors is used for the lifetime measurement with γ-γ fast timing technique. Large basis shell model calculations have been performed with the "NUSHELLX" code to interpret the low-lying level structure and to calculate level lifetimes in 131 I and 132 Xe. The measured lifetimes and absolute transition probabilities are discussed in the light of systematics with the neighboring nuclei. Single particle excitation and loss of collectivity is observed with increasing neutron number up to N = 82, validating the double shell closure at 132 Sn. Enhanced B(E1) and B(E3) strengths are found for the 1646-keV, 11/2 − level in 131 I.

The European Physical Journal A, 2005

The β-delayed proton decay of 113 Xe was investigated by means of a total absorption γ-ray spectrometer and a telescope for particle detection. The energy window available for the β-delayed proton decay of 113 Xe and the relative branching ratios for proton transitions to the 112 Te states were remeasured. The lifetimes of proton unstable 113 I states populated in the electron capture decay of 113 Xe were determined by means of the particle-X-ray coincidence technique. The results of the lifetime measurements are compared with statistical-model calculations.

2013

We report on an improved measurement of the 2\nu \beta \beta\ half-life of Xe-136 performed by EXO-200. The use of a large and homogeneous time projection chamber allows for the precise estimate of the fiducial mass used for the measurement, resulting in a small systematic uncertainty. We also discuss in detail the data analysis methods used for double-beta decay searches with EXO-200, while emphasizing those directly related to the present measurement. The Xe-136 2\nu \beta \beta\ half-life is found to be 2.165 +- 0.016 (stat) +- 0.059 (sys) x 10^21 years. This is the most precisely measured half-life of any 2\nu \beta \beta\ decay to date.

Physical Review C, 1999

The lifetimes of 12 excited states in 134 Nd were measured with a high precision by means of the GASP spectrometer applying the coincidence recoil-distance Doppler-shift method. The 110 Pd( 28 Si,xny p) reaction was used at a beam energy of 125 MeV. The data were analyzed with the differential decay curve method and the derived lifetimes were used for a sensitive test of various nuclear models. The transition quadrupole moments (Q t ) in the ground state band agree nicely with the predictions of both the rotor model and the O͑6͒ symmetry of the interacting boson approximation up to the 4 g ϩ state of 134 Nd. The Q t values for the 8 g ϩ , 10 S1 ϩ , and 12 S1 ϩ states, however, give evidence for a strong change of the nuclear deformation. The lifetimes of 12 low lying yrast states in the 130,131,132 Ce, 133,134 Pr, and 135 Nd nuclei have been also determined.

2012

The potential energy surfaces, V(β, γ), for a series of Xenon isotopes 122−134 Xe have been calculated. The relatively flat potential to 130 Xe and energy ratio E + 4 1 /E + 2 1 = 2.2 show E(5) symmetry to the nucleus which is laying in the transition region from γ-soft to vibrational characters. The interacting boson approximation model (IBA − 1) has been used in calculating levels energy and electromagnetic transition probabilities B(E2) ′ s. Back bending is observed for 122−130 Xe. The calculated values are compared to the available experimental data and show reasonable agreement.

Physical Review C, 2019

Background: The γ-softness of 136 Nd makes it possible to study the shape changes induced by two-proton or two neutron excitation. Purpose: Measurement of lifetimes of two quasi-particle states of the bands based on the 10 + states at 3296 keV and 3279 keV to investigate the shape change induced by the alignment of two protons or two neutrons in the h 11/2 orbital. Methods: The recoil-distance Doppler shift method was used for the 136 Nd studies which was formed by the fusion reaction 120 Sn(20 Ne,4n) 136 Nd, at E beam = 85 MeV. Calculations were performed within the microscopic-macroscopic approach, based on the deformed Woods-Saxon singleparticle potential and the Yukawa-plus exponential macroscopic energy. Results: The lifetime of the 10 + state at 3279 keV of 136 Nd was measured to be T 10 + 1/2 = 1.63(9) ns. The lifetimes of the 2 + state at 374 keV and of the 12 + state at 3686 keV of the ground band were also measured to be T 2 + 1/2 = 26.5(14) ps and T 12 + 1/2 = 22.5(14) ps. Conclusions: The measured lifetime of 10 + state at 3279 keV together with other observable confirm the structure change in 136 Nd. A rather small reduced hindrance of the electromagnetic decay of the 10 + state at 3279 keV would agree with its K-mixed character.

Physical Review C, 2017

The level structure of 134 Xe was studied with the inelastic neutron scattering reaction followed by γ-ray detection. A number of level lifetimes were determined for the first time with the Doppler-shift attenuation method and the low-lying excited states were characterized. From this new spectroscopic information, the third excited state, a 0 + level which had only been observed in a previous inelastic neutron scattering study, was verified. Reduced transition probabilities were calculated; comparisons were drawn with a vibrational description of the nucleus and found lacking. The 3 − octupole phonon has been confirmed, and the complete negative-parity multiplet resulting from the ν(1h 11/2 2d 3/2) configuration has also been tentatively identified for the first time in the N = 80 isotones.

2019

A. Tucholski,1 Ch. Droste,2 J. Srebrny,1 C. M. Petrache,3 J. Skalski,4 P. Jachimowicz,5 M. Fila,2 T. Abraham,1 M. Kisieliński,1 A. Kordyasz,1 M. Kowalczyk,1 J. Kownacki,1 T. Marchlewski,1 P. J. Napiorkowski,1 L. Próchniak,1 J. Samorajczyk-Pyśk,1 A. Stolarz,1 A. Astier,3 B. F. Lv,3 E. Dupont,3 S. Lalkovski,6 P. Walker,7 E. Grodner,4 and Z. Patyk4 1Heavy Ion Laboratory, University of Warsaw, Pasteura 5a, 02-093 Warsaw, Poland 2Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warszawa, Poland 3Centre de Sciences Nuclaires et Sciences de la Matire, CNRS/IN2P3, Université Paris-Saclay, Batiment 104-108, 91405 Orsay, France 4National Centre for Nuclear Research, Hoża 69, 00-681 Warsaw, Poland 5Faculty of Physics and Astronomy, University of Zielona Gora, Licealna 9, 65-417 Zielona Gora, Poland 6Nuclear Engineering, Faculty of Physics, Sofia University “St. Kl. Ohridski”, 5 James Bourchier Boulevard, Sofia 1164, Bulgaria 7Department of Physics, University of Surrey, Guildford G...

Physical Review C, 2014

We report on an improved measurement of the 2νββ half-life of 136 Xe performed by EXO-200. The use of a large and homogeneous time projection chamber allows for the precise estimate of the fiducial mass used for the measurement, resulting in a small systematic uncertainty. We also discuss in detail the data analysis methods used for double-beta decay searches with EXO-200, while emphasizing those directly related to the present measurement. The 136 Xe 2νββ half-life is found to be T 2νββ 1/2 = 2.165 ± 0.016(stat) ± 0.059(sys) · 10 21 years. This is the most precisely measured half-life of any 2νββ decay to date.